This invention relates to the preparation of plastic containers, especially composite parisons having a preformed inner sleeve or lining, said parisons being useful in the formation of composite blow molded containers as described in my prior U.S. Pat. Nos. 3,719,735 and 3,717,544. According to said patents, previously formed sleeve-like liners are applied to a blow core of an injection blow molding apparatus, plastic is injected around said liners while upon the cores and the resultant composite parison, consisting of the liner and the injected plastic, is expanded together into conformance with a blow mold. The method of injection blow molding is well known and described, for example, in U.S. Pat. No. 3,029,468 and others.
Many articles of the foregoing type require decoration, either by the application of labels or by printing on their visible surfaces. In accordance with known processes difficulties are frequently encountered when decorating plastic articles of the foregoing type. For example, the use of labels on the outer surfaces is often considered unattractive and these labels tend to be frequently damaged in shipping and handling. All too often the labels adhere poorly and are completely removed from the article, leaving one in doubt as to the identity of the contents of the articles.
It is known to use heat transfer decorating with decals from a previously printed web of plastic that may be made to adhere to the article by heat and pressure. This procedure, however, is relatively expensive and is limited by the shape of the article to which it may be applied.
The art frequently accepts the disadvantages of labels and decals because they may be printed on roto-gravure presses at high quality levels. However, it would be highly desirable to overcome the disadvantages associated with these methods.
An additional procedure for decorating articles of this type is to print directly thereon. Several procedures may be employed to accomplish this, such as screen printing, elastic pad transfer, offset printing, etc. Unfortunately, different printing processes have different drawbacks when used in connection with articles of the foregoing type. Thus, for example, offset printing is capable of achieving excellent quality, but only if the surface upon which it is to be applied is rigidly supported. A cup or can shape, into which a mandrel may be inserted to support the walls, may be offset printed with excellent quality, in multi-color halftones. A bottle, whose walls cannot be so supported from the inside, is offset printed with inferior quality. Another drawback of offset printing is that one must limit the kind of ink which must be used in connection with most plastics. The suitable inks tend to be of low abrasion resistance and proor adhesion. The better quality inks often cannot be used on plastic articles because they frequently require heat setting at temperatures to which the printed articles cannot be exposed without loss of shape.
Accordingly, it is a principal object of the present invention to provide a method for making decorated plastic articles, and a decorated plastic article which is conveniently and inexpensively obtained and versatile so that it may be used with a variety of printing methods, such as labels, decals and direct printing.
A further object of the present invention is to provide a method and article as aforesaid wherein the decorated surface is protected from such hazards as abrasion damage, shipping damage, poor adhesion and the like, while remaining entirely visible and esthetically attractive.
An additional object of the present invention is to provide a method and article as aforesaid utilizing composite plastic articles.
Further objects and advantages of the present invention will appear hereinafter.